Peanut oil is famous for its rich nutrients, and is one of edible oil products sold at the highest price among edible oil products in the market. Under normal conditions, peanut oil is in light-yellow, transparent, and clear color and luster, with aromatic smell and delicious taste, and is an edible oil product easy to digest. Peanut oil contains unsaturated fatty acids at 80% or higher percentage (including 41.2% oleic acid and 37.6% linoleic acid). In addition, peanut oil contains saturated fatty acids such as palmic acid, stearic acid, and arachidic acid. Moreover, peanut oil contains substances beneficial for human body, such as sterol, maltol, phosphatide, vitamin E, and choline, etc. It is seen from above data that the fatty acids in peanut oil are easy to digest and absorb by human body. Reports in foreign countries state that eating peanut oil regularly not only is helpful for decomposing cholesterol in human body into bile acids and excreting the bile acids out of human body, but also can reduce the content of cholesterol in blood. In addition, eating peanut oil regularly can prevent skin cracking and aging, protect blood vessel wall, prevent thrombosis, and is helpful for preventing arteriosclerosis and coronary heart diseases. The choline in peanut oil can improve brain retentivity and postpone brain function declination. It is seen that peanut oil is an edible oil product highly beneficial for human health. However, driven by interest pursuing, peanut oil adulteration activities remain incessant after repeated prohibition.
The high price difference between peanut oil and rapeseed oil/palm oil/soybean oil (at present, in the market in Guangzhou, China, the price of peanut oil is approx. RMB10,250/t, while the price of soybean oil is RMB5,400/t, the price of rapeseed oil is RMB6,150/t, and the price of palm oil is RMB4,380/t) provides an opportunity to unscrupulous vendors. These vendors or individuals adulterate other vegetable oils in peanut oil, or even replace peanut oil with other vegetable oils completely, with a small amount of peanut oil essence mixed for flavor treating. However, such adulterate peanut oil is usually hard to distinguish solely by means of smelling or refrigeration. Therefore, it is highly necessary to develop a detector that can distinguish adulterated peanut oil.